Oxygen regenerator



April 8} 1952' -P. 5. ROGERS ETAL 2,591,878

OXYGEN REGENERATOR 2 SHEETS-SHEET 1 Filed Sept. 22, 1948 April 8, 1952P. s. ROGERS ETAL 2,591,878

OXYGEN REGENERATOR Filed Sept. 22, 1948 2 SHEETS-SHEET 2 Patented Apr.8, 1952 Philip S. Rogers, Willard 0. Emmons, John W. Godfrey and JamesMilton 'Kelso, Lockport, N. Y., assignors to General Motors Corporation,Detroit, Mich., a corporation of Delaware Application September 22,1948, SerialNo. 50,496

. 1 For the production of tonnage oxygen atmospheric air can be cooledto a very low temperature and then separated by distillation andrectification into its main constituents, namely, oxygen and nitrogen.Efiiciency of the process is increased by pre-coolingthe incomingcompressed air and this conveniently and economically can be donethrough the utilization of cold oxygen produced by the process and thecold waste nitrogen. For working the low temperature products for theabsorption of heat from the compressed air an oxygen regenerator can be.employed and so arranged as to serve also as a purifier of the air byremoval of normally present moisture and carbon dioxide. Purification isaccomplished by the temperature drop in that as the air becomes verycold the impurities condense on the heat exchange surfaces over whichthe air sweeps.

By periodically switching the paths of air and nitrogen through thedevice the nitrogen as it 6 Claims. (Cl. 257-245) row of pinssuccessively joined by return bends at their opposite ends.

An important feature of the present invention is the elimination offlexibility in the coiled wire during handling and the provisionautomatically for proper location in the assembly by fitting or nestingthe return bends at least along one end within a channel section stripwhich gives stifiness and provides spacer flanges or separators for theneighboring lengths of coiled wire when they are placed side by side forbrazing or like T Figure l is a perspective View of an oxygen rewarms upin absorbing heat from the air acts to 1 vaporize moisture and carbondioxide previously deposited from the air and carries out the impuritiesto complete the cycle.

For working the fluids to best advantage it is important that anabundance of surface be exposed in the flow paths without too muchrestriction to flow and that relatively thin walls separate adjoiningpassages. Italso is of consequence to incorporate ruggedness in theassembly of thin walls. These things are substantially achieved togetherwith ease and simplicity of manufacture by the employment in general ofa succession of spaced flat sheets closed at their edges to affordpassages therebetween'and held apart throughout their width and breadthby a multiplicity of spaced struts in the nature of small diameter pinsarranged in rows andjoined at opposite ends to the opposing faces ofadjacent 7 thin walls.

The thinness and multitude of pins provides large surface area exposedwithin the small passages and their arrangement in longitudinal rowsnarrowly spaced apart minimizes resistance to fluid flow while insuringthe sweeping of the surface by a maximum number of fluid particles.

To avoid the need during manufacture and assembly for handling the pinsindividually it is here proposed that all pins of each successive pairof rows be formed of one continuous piece of wire which can be handledas a unit and this contemplates the use of a serpentine or helical coilhaving straight or flattened sides or a narrow elongated loop formation.Thus the long straight sides of each helix constitute a doublegenerator; Figure 2 is an end view thereof; Figure 3 is a broken awayfragment in perspective; Figure 4 is an enlarged detail perspective of afew rows of coils with end loop locatorchannels fitted alternately toopposite ends of neighboring helical lengths of wire and Figure 5 is asection on line 5--5 of Figure 2.

In the drawings the assembly is illustrated as comprising a group offlat plates 6 in superposed spaced relation affording a stack of fluidflow passages which cormnunicate selectively at one end with connectorpipes or tubes 1, 8, 9 and I0 and at the opposite end with similarconnector pipes la, 8a, 9a and Ito.

As shown there are six passages and as pest seen in Figure 2 it will benoted that the first and the fifth passages are joined with the connector tubes 8 and m; that the second and sixth passages are joined withconnector tubes 9 and So; that the third passage is joined with theconnector tubes 1 and la and that the fourth passage is joined with theconnector tubes H and Illa. The construction is such that the unit maybe placed in the oxygen producing system for fluid flow in eitherdirection. The several con-- nector tubes are to be coupled by suitablevalving which controls the flow of fluids through thepassages. Thus inone setting of the selector valves the connector tubes Ill and lta willcarry oxygen after having been separated in the processing treatment;the connector tubes 7 and la will carry unbalanced air; the connectortubes 9 and 9a will carry compressed air to be treated and'whosetemperature is to be lowered beforehand with an accompanying deposit ofimpurities and the connector tubes 8 and 8a will carry cold nitrogen. Asan example of a resetting of the valves the compressed air to be chilledwill be directed through the passages joined with the tubes 8 and 8a andthe waste nitrogen will be directed through the passages joined by theconnector tubes 9 and 9a and in taking on heat will vaporize and carryaway those impurities previously deposited in the passages.

A stack of thin wall plates, while promoting rapid heat transfer andhaving the advantage of lightweight, have a more important significancewith reference to making up a smaller and more efficient package withgreat ruggedness by supplementing the wall surface area through the useof internal stiffening struts secured to the Walls and extending acrossthe passages. Thus in the regions near opposite ends of each passage itis proposed to insert the serpentine ribbons H set on edge for brazedattachment to the opposing faces of passage Walls with their successivestraight lengths extending transversely of the passage. These strips I iare apertured or formed throughout their length with a series of spacedand relatively large openings and since they are located immediatelyadjacent the fluid inlet and outlet connections which occupy arelatively small part of the width of the passage they serve not only asstiifeners and as increased radiation surfaces but also as spreader'bafiies for the incoming fluid flow in that the fluid traveling fromend to end will be more uniformly distributed throughout the passage.Through the intermediate length of each passage and extending inlongitudinal rows transversely spaced apart are the pin struts it, eachjoined at opposite ends to the opposing surfaces of the passage and extending; on a straight line across the passage space.

By making the pins E2 of small diameter in relation to their length andspacing them closely together a very large number can be accommodatedand they insure an abundance of surface area for carrying heat to andfrom the walls and for exposure to fluid flow. Their arrangement in rowsminimizes fluid resistance. They are here constituted by successivestraight runs of flattened helical coils of wire. The elongatedconvolutions are wrapped on a flat mandrel or otherwise formed so thatsuccessive wire pins have their opposite ends joined by return bends orend loops. fhus each continuous piece of helical wire consists of twospaced apart rows of spaced apart pins together with opposite endconnecting loops. It is proposed that all the loops at least at one endof the elongated convolutions shall be nested or fitted within a channelsection stiffener strip It. By fitting the channel to the coils as asubassembly the pins will be securely located and held againstdeflection and injury and rendered more convenient to handle. Theseveral wire subassemblies may be placed side by side with the endchannels alternately arranged for fixed abutment with the opposing facesof the passage walls. In this fashion the side flanges of the channelsserve to space apart the neighboring wire helices at both the top andbottom, as viewed in Figure 4, with the flanges of the alternatelydisposed channels cooperating in succession and being aligned in pairsin common planes.

For ease of manufacture each intermediate wall plate 6 is transverselyslitted for a short distance inwardly at each side and the materialbetween the slits is alternately pressed upwardly as at M and downwardlyas at 5 and preferably also formedwith terminal outwardly extendinghottoming flanges, not shown. Similar formations extending downwardly,as at It, on the uppermost' wall'plate' and upwardly, as at IT, on thelowermost wall plate are also provided and the purpose of these severaltabs is merely to space and locate the plates during the assemblyoperation and the subsequent brazing operation. Thereafter all of thetabs or if desired only the outwardly extending terminal portions may besheared 01f completely.

For leakproof closure of the sides and ends of the passages between thestack of plates and for increased structural strength at the sides thereare employed spacer bars [8 of relatively thick material insertedbetween the successive plates 6-6 at their edges at all four sides ofthe assembly. The use of such bars for closing purposes enables thetemporary spacer tabs to be sheared off, as previously referred, to. Theclosure bars IS in the opposite ends of the assembly are arranged so asto leave openings for communication with the respective connector tubes.Thus by reference to Figure 5 it will be seen that the connector tube 8is a short length of pipe having screw threads formed on one end forcoupling purposes and having its opposite end closed by a cap l9 andbeing formed with a pair of s10ts on one side in alignment with two ofthe passages in the plate stack; Each slot I9 is enclosed by top andbottom plates 2li29 having circular openings defined by marginal flangesor collars 2i into which the tube is fitted. Between the outer edges ofthe cooperating plates 2Ei26 is-a U-shaped closure bar 22 to completethe fluid carrying conduit between the connector tube 8 and the heatexchanging passage. For adding stiffness a corrugated plate 23 isinserted between each set of plates 2ii20 with its corrugationsextending in the direction of flow and constituting struts which tie theplates together. In like manner communication is provided between theremaining passages and their respective connector tubes.

After the several parts have been preformed they are broughttogetherinto the final stack assembly relation and by means of suitable locatingfixtures they are so held and then placed in a brazing oven andintimately bonded at all-points of abutment. According to conventionalpractices the brazing material may be precoated on such contactingparts.

We claim:

1. In an oxygen regenerator or the like, a succession of superposed flatwall plates spaced apart, side and end closures for the spaces betweenthe plates to thereby form a stack of sealed fluid flow passages, aseries of inlet connectors arranged side by side at one end in selectivecommunication with the fluid flow passages for delivery of severaldifferent fluids in staggered relation to successive fluid flowpassages, a series of outlet connectors similarly arranged at theopposite end and each connector communicating with its fluid flowpassage through an endclosure for a distance constituting a smallfraction'of the passage width, apertured serpentine distributors locatedin the opposite ends of the passages and set on edge with opposite edgesjoined to the adjacent faces of said plates and thereby stiffeningthe'plate assembly, a series of flattened coils ofhelically wound wireextending longitudinally of each passage in transversely spaced side byside relation and with spacers between adjoining side lengths of theadjoining flattened coils, said spacers comprising longitudinallyextending cha-nnels fitted in nested relation to the coil end loops, onefor each coil and arranged-alternately on opposite end loops and securedby brazing or the like to both the wire coils and the plate surfaces.

2. In combination, spaced apart conduit walls, a series of flattenedcoils of wire arranged side by side within the space between said wallsand with their straight portions extending across the space and theirreturn loop portions adjacent opposite walls, and elongated elements ofchannel shape in transverse section, one for each coil, fitted in nestedrelation to said loop portions, said elements being fitted to endsopposite one another on succeeding coils and being alternately securedto opposing wall faces with the flanges thereof cooperating with oneanother to bear on and space apart the neighboring coils, said returnloop portions extending generally transversely of said channels.

3. In a device of the character described, flat walls spaced apart toprovide fluid flow space therebetween extending between an inlet and anoutlet, channeled locator strips secured in parallel spaced relation onthe opposing faces of said walls with the channels carried by opposingfaces in offset staggered relation and arranged so that successivechannel side flanges, extending inwardly from each face, are uniformlyspaced apart and in planes common to successive flanges on the opposingface and a group of pin struts extending between opposing wall faces,comprising a succession of flat helical coils of wire having spacedapart straight side strut portions successively joined at opposite endsby return bends which nest between and are secured to succeedingflanges, said return bends extending transversely of said channels.

4. In an oxygen regenerator or the like, a stack of superposed passagesfor the flow of several different fluids, the walls of adjacent passagesbeing common to said adjacent passages, each passage including spacedapart flat wall plates andhaving an inlet and an outlet spaced apart andnear opposite ends of the passage; a row of spaced apart perforateddistributor strips positioned between said wall plates adjacent each ofthe opposite ends of the passage near the inlet and outlet respectively,with each strip corresponding in width to the space between said wallplates and being set on edge and extending in a plane substantially atright angles to said wall plates, said strips being joined alongopposite edges to adjoining faces of both plates; and a group of spacedpins throughout the passage between said rows of distributor strips,said pins comprising the straight sides of a series of flattened helicalcoils of wire whose opposite end loops are joined to said plates.

5. In an oxygen regenerator or the like, a group of spaced apart flatwall plates affording fluid passages therebetween, each passage havingan inlet and an outlet for the entry and exit of fluid;

spacer pins within the passages comprising flattened helical coils ofwire, each coil including two spaced apart rows of spaced apart pinportions, the successive pin portions in each row having their oppositeends joined by returnbends to adjacent pins in the opposite row, saidcoils being arranged'in side by side spaced apart relation; andelongated spacer flanges fitted between the pin portions of adjacentcoils and being arranged alternately on opposite return bends of thecoils and secured to said walls, said flanges extending in theirlongitudinal dimension generally transversely of said return bends.

6. Apparatus of the character described, including, means providingparallel spaced apart flat walls providing a fluid flow passagetherebetween with an inlet and an outlet thereto; a plurality offlattened helical wire coils between the walls, each coil including twospaced apart rows of spaced apart pin portions extending at right anglesto the surfaces of said walls, the successive pin portions in each rowhaving their opposite ends joined by return bends to adjacent pins inthe opposite row; and elongated coil spacing elements of channel shapein transverse section, said elements being fitted in nested relationover said return bends and having side flanges in bearing contact withadjacent coils to space said adjacent coils apart, said return bendsextending generally transversely of said channel elements.

PHILIP S. ROGERS.

.. WILLARD O. EMMONS.

JOHN W. GODFREY. JAMES MILTON KELSO.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,409,967 Prat Mar. 21, 19222,093,256 Still Sept. 14, 1937 2,308,319 Stanton Jan. 12, 1943 2,439,208Gloyer Apr. 6, 1948 FOREIGN PATENTS Number Country Date 559,107 GreatBritain Feb. 3, 1944 574,949 Great Britain Jan. 28, 1946

